Well logging instruments that utilize radiation generators, such as sealed-tube neutron generators, have proven incredibly useful in oil formation evaluation. Such a neutron generator may include an ion source and a target. Some ion sources operate by emitting electrons from a cathode, and accelerating those electrons to suitable energies in the presence of an ionizable gas. Once the ions are created by interactions between the electrons and the ionizable gas, they are accelerated to a target that emits neutrons when struck by the ions. Therefore, the rate of neutron production in such a radiation generator is related to the rate of ion production, which in turn is related to the rate of electron production.
Consequently, it is desirable for the production of electrons to remain substantially constant in such a radiation generator, and the creation of new cathode assemblies that help to provide a substantially constant electron output is desirable.